1. Field of the Invention
This invention in general relates to the field of iontophopretic introduction of ionic substances into a body, and more particularly concerns an improved device which simplifies the iontophoretic administration of ionic substances, and permits a patient to be normally ambulatory during the administration of the substance.
2. Description of the Prior Art
Iontophoresis is a method for introducing ionic substances into a body. The method utilizes direct electrical current to drive the ionized substances, such as chemicals or drugs, through the intact skin or other body surface. This has proven to be very useful in numerous medical applications. See U.S. Pat. Nos. 3,991,755 issued to Jack A. Vernon, et al, 4,141,359 issued to Stephen C. Jacobson et al. Prior art iontophoretic devices generally comprise an iontophoretic current generator and a pair of electrodes. The electrode containing the ionic substance to be introduced into the body is generally known as the active electrode while the other electrode is called the ground or indifferent electrode. The current generator is generally a hand-held or table-supported instrument and the electrodes are connected to the generator by means of wires. The electrodes, especially the active electrodes, generally are relatively complex devices, including a cup or other receptacle for holding a fluid solution of the ionic substance in contact with the body, a means for making electrical contact with the solution, and a means for holding the electrode firmly to the body. Such electronic devices also require the use of some means for introducing the solution containing the ionic substance into the electrode receptacle, such as a syringe. Relatively high skill levels are thus required for the use of the prior art iontophoretic devices (compared for example to the skill required to apply a bandage). These devices also require the patient to remain in a fixed location during iontophoretic processes, which is a decided disadvantage since the process generally takes time on the order of minutes or sometimes, hours.
U.S. Pat. No. 4,141,359 discloses a compact iontophoretic device in the embodiment shown in FIG. 2 and discussed in Example I of that patent. In this device the grounding electrode is mounted on the current generator housing and tne indifferent electrode is connected to the housing by a wire. This device may be entirely mounted on the body of the patient and thus, presumably some motion of the patient is possible while the device is in use. However, the use of this device still requires a relatively high level of skill and care since the electrodes are of the fluid gel-type. In addition, the gel-type electrodes are subject to some movement on the skin, and the wire can be snagged during movement. Thus, this device does not readily lend itself to ambulatory type applications, especially in the case of young children who tend to have highly mobile limbs.